I think that loaning would be a perfect suggestion for the game.
For ex.I need an veteran player but for 1 season,but thats all i dont need him anymore,i dont someone which ibought him for an really expensive price to stay all time on the bench after i am done with him.
Ex.2.My most important player is injured and he needs 5 days to recover.On this days I have the most important matches of the season.So what,I must stay all time on the transfer market to find a player like him and i REPEAT iT he is my most important player which means he is really good and to find a relly good player I must spend a lot of cash.Lets not mention the whole wasted tokens!

The period the player will be loaned would be minimum:1 week,maximum:1-2 seasons.
Of course also the period between them.{time}